go to "Sim Lim Square" lots of camera's and computer stuff
accross the street you'll find "Sim Lim Tower" where you can find very cheap electronic parts and stuff like that
"Bugis" is nice as well, on the market you can find all kind of fake shit
"SunTec City" is a huge mall and I mean HUGE
On "Orchard Road" you can buy the expensive goods for your wife
Have a pleasant stay!